Belting of woven fibrous material



I I or alcohol for dissolving the Patented Sept. ,17, 1929 UNITED STATESPATENT OFFICE ERNST WOLFGANG KOHLSCHllTTER, F HAMBURG, GERMANY BELTI'NGOF WOVEN FIBROUS MATERIAL NdDrawing. Application filed Tune 1, 1927,Serial No. 195,857, and in Germany April 13, 1926.

For impregnating belting made of woven fibrous material benzol solutionsof gutta-' percha-like asphzaltic bitumens have been found to be themost satisfactory. These bitumens, however, always contain considerablequantities of greasy paraflinic constituents which for some uses, towhich the belting is put, are found to be inconvenient, for instancewhen such impregnated belting-is used for brake bands, but moreparticularly when these impregnated beltings.

are to be subsequently covered on both sides with caoutchouc or thelike.

The following process has proved succesful placed in a pressure vessel.which can be heated by means of a steam jacket or heating coils, and thevesselis thereupon closed and evacuated.

A solution of 1 part of asphaltic bitumens similar in plasticity togutta-percha in 1 to 2 parts of commercial benzol is thereupon allowedto flow into the vessel, and the whole is then heated by means of thesteam jacket or the heating coils up to.

slightly above 100 C. As is well-known, hot benzol is sufiicientlycapable of dissolving .the small quantities of moisture which are drivenout of the fibres at a temperature' of slightly above 100 C. The

heating produces a pressure of several atmospheres inv the vessel. Avalve in the bottom of the vessel is thereupon. opened '35 and the hotimpregnating solution allowed to flow out into a suitable receptacle,

The finished woven fibrous belting his.

constituents of the bitumen will be removed to a sufficient extent. Theacetone or alcohol solution is again allowed to flow into a suitablereceptacle after which a vacuum is again produced. The last traces ofthe soltreating the impregnated belting with a solvent' for the greasyparafiinic constituents only of the bitumens.

In testimony whereof I have signed name to this specification.

ERNST WOLFGANG KOHLSCHlilTTl-IR.

whereupon the bottom valve is closed and I a vacuum again produced,causing the im pregnating solution retained in the fibrous 40 belting bycapillary action to be evaporated.

At the same time the last traces of water evaporate which have beensplit off out of the fibres. A sufficient quantity of acetone 'reasypar'af 4 finic constituents of the aspha tic,bitumens used is thenallowed. to flow into the vessel,

9. pressure above that of-the atmosphere being again produced byapplying heat -by' means of the steam jacket or the heatin v50 coil. Bythis meansthe greasy parafiimc

